$A$ gas deviates maximum from the ideal gas law at

$A$ system consists of two types of gas molecules $A$ and $B$ having the same number density $2 \times 10^{25} \, /m^3$. The diameters of $A$ and $B$ are $10 \, \mathring{A}$ and $5 \, \mathring{A}$ respectively. They undergo collisions at room temperature. The ratio of the average distance covered by molecule $A$ to that of $B$ between two successive collisions is $..... \times 10^{-2}$.

What is free path? And what is mean free path?

For matter to exist simultaneously in gas and liquid phases:

For the given concentration,if the ratio of the diameters of the molecules of two gases is $1: 2$,then the ratio of their mean free paths is

In Van der Waals equation $\left( P + \frac{a}{V^2} \right)(V - b) = RT$,what do $a$ and $b$ represent?